Electrically operated pump assembly



March 27, 1 s. lMMOVlLLl 3,026,808

ELECTRICALLY OPERATED PUMP ASSEMBLY Filed Feb. 18, 1960 2 Sheets-Sheet 1 500 497/ y iPJHhN-u 96mm 40 IN V ENTOR.

Filed Feb. 18, 1960' March 27, 1962 s. IMMOVILLI 3,026,808

ELECTRICALLY OPERATED PUMP ASSEMBLY 2 Sheets-Sheet 2 l l kwm 691A INVENTOR. BY @1410 W United States Patent ELECTRICALLY OPERATED PUMP ASSEMBLY Silvio Immovilli, Ing. A. Giambrocono, Via Burial 4,

- Milan, Italy Filed Feb. 18, 1960, Ser. No. 10,836 3 Claims. (Cl. 103-87) This invention relates to electrically-operated pump assemblies such as may be employed, for example, in forced circulation systems of hydraulic or thermal installations. The object of the present invention is to avoid certain disadvantages arising from the construction of known forms of electrically-operated pump assemblies. One of these disadvantages is the use of a stuffing box to provide a fluid-tight connection between the shaft of the pump impeller and the shaft of the driving motor. The stufiing box represents a source of losses of a hydraulic character when the motor is disconnected from the pump. Also by using a stuffing box the expeditious replacement of the driving motor of the assembly is rendered extremely difficult and, therefore, in order to change the motor a lengthy suspension of operation is required. 7

An electrically-operated pump assembly according to the present invention comprises in combination a pump impeller, a casing within which the pump impeller is housed, an electric motor disposed rearwardly of the pump casing and having a rotor assembly and a stator assembly disposed within a casing frame, a plate member secured to the forward end of the casing frame of the stator, securing means for attachment of the casing frame at the forward end thereof to the casing of the pump, a shaft mounted wthin bearings respectively provided on the pump casing and the casing frame of the stator assembly and extending within the stator assembly, the shaft removably carrying the pump impeller at a forward end thereof and the rotor assembly on an intermediate part thereof, and a valve mechanism adapted to open upon mounting of the casing frame of the motor on the pump casing to permit passage of liquid from the pump casing to the interior of the casing frame and further adapted to close and thereby inhibit flow of liquid from the pump casing detachment of the motor casing frame from the pump casing.

Thus by use of the present invention the Working liquid of the pump is used to lubricate the motor and the need for a stufi'ing box is avoided. Also the ready removability of the motor stator casing and parts therein from the pump casing enables the motor to be expeditiously replaced thereby reducing loss of operating time to a minimum.

The invention will now be described, by way of example, With reference to the accompanying drawings, in which:

FIGURE 1 illustrates a longitudinal section elevation of an electrically-operated pump assembly according to the invention;

FIGURES 2 and 3 which are drawn to a larger scale than FIGURE 1 illustrate in greater detail the part of FIGURE 1 marked with the reference A which includes a valve mechanism, FIGURE 3 showing the valve mechanism in the open position and FIGURE 4 showing the valve mechanism in the closed position;

FIGURES 4 and 5 are views similar to FIGURES 3 and 4 but illustrating a further embodiment of the invention; and 1 FIGURE 6 is a View taken on the line VI-VI of FIGURE 5 and drawn to a larger scale than FIGURE 5.

Referring first to FIGURES 1 to 3 of the drawings, an electrically operated pump assembly comprises an electric motor generally indicated by the reference M part 200 (connected to a cover plate 202 by screws and a pump generally indicated by the reference P. The motor M includes a stator assembly and a rotor assembly 101 whilst the pump P includes a casing or body 201) and an impeller 203.

As shown in FIGURE 1, there is provided a shaft 205 on a forward end of which is mounted the impeller 203 whilst on an intermediate portion of the shaft 205 the rotor assembly 101 is secured. The shaft 205 is rotatable in bearings 206 and 207 of which the bearing 206 is mounted in a rearwardly projecting annular boss 202a disposed re-arwardly of the impeller 203, whilst the bearing 207 is accommodated in a forwardly extending annular part 116 secured to and forming part of the stator assembly 100.

The stator assembly comprises a casing frame within which are secured magnetic pole elements such as element 111 and mounted on the pole elements are field windings 112 which are retained in position at the rear thereof by a forward extension of the annular part 116 and at the front thereof by central rearwardly extending annular boss provided on a plate member 113 secured by screws 114 to the frame 110. At the rear end of the part 116 there can be provided a transparent cover 120 through which it is possible to see whether the shaft 205 is rotating.

The'shaft 205 at the 'rear end thereof is formed with flats 205a to permit manual rotation of the shaft for disengaging it from any build up of corrosion which may take place in the course of time.

Screws 300 are provided for securing together the frame 110, the plate member 113 and the cover plate 202. Thus the entire stator assembly, consisting of plate member 113, magnetic pole elements 111, field windings 112, annular part 116, frame 110 and cover 120, can be detached as a unit merely by unscrewing the screws 300. g The stator assembly can therefore be replaced with minimum loss of operating time in the event of damage thereto or a fault arising.

The valve mechanism V illustrated in greater detail in FIGURES 2 and 3 will now be described. When the stator assembly is mounted on the rotor the valve mechanism V opens to permit passage of water for purposes of lubrication from the pump as indicated by the arrow 1 to the interior of the motor M. The valve mechanism is automatically shut when the stator assembly 100 is removed from the pump P. As shown in FIGURES 1, 2 and 3 the valve mechanism V includes a screw threaded stem 400 freely passing through an aperture 401 formed in the cover plate 202. A helical biassing spring 404 is mounted on the stem 400 and acts between the plate 202 and a spring anchor part 403, this latter part being screwed onto the rear end of the stern 400 and secured thereto by a nut. The aperture 401 includes at its forward end a frusto-conical section 202b and at its rear end a section of uniform diameter. The frusto-conical section 202b of the aperture 401 provides a seating for a complementary shaped head part 405 at the forward end of the stem 400.

When the stator 100 is removed, the spring 404 so biasses the stem 400 of the valve mechanism that the head 405 engages the seating 202b and flow of water from the pump through aperture 401 is prevented. On mounting the stator on the pump, the stern 400 is moved axially against the action of the spring 404 and the head 405 of the stem is disengaged from its seating 202b to permit passage of water from the pump P, through the aperture 401 and into the interior of motor M.

Referring now to FIGURES 4, 5 and 6 the valve mechanism V instead of utilising the spring 404 may include a block 410 of rubber or the like resilient material mounter on the stem 400 and secured thereto against rearward movement by means of a nut 403a. In the surface of the block'4 10-adjacent the cover plate 202 are formed radially extending channels 415 through which can flow water, from; the aperture 401 tothe interior of a the motor M. When the stator is-not mounted on the pump, the block 410 urges the stem to the rightas-shown in FIGURE so that the stem'head405 engages the seating-202k and the valve mechanism is closed. "When the-stator is mounted on thepump; however, the stem is forced to'the rightas seen in FIGURE 4 and the stem head 405 is displaced from the seating 2025. In this position water can flow from the pump by way of the aperture-40 1 and the channels 415 to the interior of the motor.

It will -be apparent that asthe connectionof .the pump touthe-interior -of the -motor by; way'of ap'erture'401 is automatic upon mounting of the stator, the danger of water from thepump squirting onto the maintenance operator of the apparatus is avoided. s Q i The electrically-operated pump assembly'according to the invention by utilising the working liquid of the pump for lubricationof the motor-avoids the use of a stufling box for providing the connection between the impeller and:theimotor shaft'andthe hydraulic losses occasioned thereby when the motor is disconnected from the pump;

Also the ready replaceability of; the motor part of the:

assemblyensures that loss of operating timeis minimised.

What I claim is: h u 1:. -An electrically-operated pump assembly comprising in combination a pump impeller, a casingwithin which the pump impeller is housed,- an electric motor disposed rearwardly of the pump casing and -having'-a""rotor-assembly and a stator assembly-disposed vwithin a casing frame; aplate membersecured to thegforwardend of the casing frame of thestator, securing means for'attachment' of the casing frame at the forwardendthereofto the casing of-the pump; afirst-bearing provided on the pump casing -and asecondbearing'providedon the casing frame of the stator assembly,-- a shaft-mounted within the said first and second bearingand' extending within the stator assembly, the shaft removably carrying the pump impeller at a forward end thereof and the rotor assembly of the aperture.

stemlextending within an aperture formed in'the pump casing and projecting rearwardly from the pump casing a complementary valve seating formed from the said aper ture, a'valve head provided on the forward end ofthe stem and adapted to co-operate with'the said complementary valve seating provided in the aperture and 'a biassing spring acting between the pump casing and the valve stem and serving to bias the valve stem to a position in which the valve head is engaged on its seating.

3. An electrically-operated pump assembly as claimed in claim 1, wherein the valve mechanism includes a valve stem extending within an aperture formed in the pump casingand projecting rearwardly from the pump casing a complementary valve seating formed from said aper tures, a' valve'he'ad-provided' on the forward end of the stemand adapted to co-operate'with the said complementary valv'e seating provided in the aperture, and a" a block' of resilient material mounted on'the stem and acting" between the stem and the pump casing tou'r'ge' the stem to a position in which the valve head is engaged 'on'its seating, the resilient block being formed on the surface thereof adjacentthe pump casing with radial channels adapted, when the valve mechanism is opened by compressing' of the resilient block against the pump casing, to p'ermitfi'ow of liquid out of the pump casing by way References Cited: in the: file ofthis patent UNITEDJ'STATES PATENTS 2,688,946 Jarsaillon Sept. 14, 1954 

